Winged yam is an herbaceous, twining vine that can grow to lengths exceeding 30 ft. (9.1 m). It invades open to shady areas in the extreme southeastern United States. Leaves are opposite, 8 in. (20.3 cm) long and narrowly heart-shaped with long petioles. The stems are square with the corners compressed into wings. The chief means of reproduction is by aerial potato-like tubers (bulbils) located at the leaf axils and by underground tubers. The vine rarely flowers. Winged yam can form dense masses of vines that cover and kill native vegetation including trees. It was introduced from Asia as a possible food source in the early 1800s. In some countries it is presently being cultivated for medicinal uses.